Bell YOH-4

The Bell YOH-4, originally designated YHO-4, was a single-engine, single-rotor light helicopter developed by Bell Helicopter for the United States Army Light Observation Helicopter competition. Bell submitted its Design 250 in January 1961 and built five prototypes as the Model 206 in 1962, the first of which made its maiden flight on 8 December 1962. Nicknamed the Ugly Duckling, the YOH-4A lost the original competition to the Hughes OH-6 Cayuse, which was selected in May 1965. Bell then redesigned the body into the sleeker Bell 206A JetRanger for the commercial market, where it enjoyed instant and lasting success, and when the Army reopened the competition in 1967 it chose the 206A-based OH-58 Kiowa.